Tuyere construction for underfeed stokers



May 31; 1949. THOMAS 2,471,797

TUYERE CONSTRUCTION FOR UNDERFEED STOKERS Filed Dec. 25, 1944 5 Sheets-Sheet 1 IN V EN TOR. fDW/MD 5 77/0M/7 May 31,1949;

TUYERE CONSTRUCTION FOR UNDERFEED STGKERS Filed Dec. 25, 1944 3 Shets-Sheet 2 INVENTOR. fPW/MD 3. 77/0/7/75.

E. B. THOMAS 2,471,797

May 31, 1949. E. BQ THOMAS 2,471,797

TUYERE CONSTRUCTION FOR UNDERFEED STOKERS Filed Dec. 25, 1 44 5 Sheets-Sheet 3 Patented May 31, 1949 TUYERE CONSTRUCTION FOR UNDERFEED STOKERS Edward B. Thomas, Middletown, N. Y., assignor, by mesne assignments, to Chrysler Corporation, Highland Park, Mich, a corporation of Delaware ApplicationDecembcr 23, 1944, Serial No. 569,483

"2 Claims. 1

This invention relates to a tuyere construction particularly applicable for use in anthracite burning furnaces havin underfeed stokers.

In a tuyere construction of this character it is desirable that it be built up of a series of separate units fitting together and removably supported above and about the retort to provide a support for the solid fuel upwardly therein while admitting air for efficient combustion. It is advantageous both for installation and production to employ a series of unit castings which may be fitted together and assembled for this purpose.

In the burnin of anthracite particularly, as well as other kindred solid fuel, it is desirable that the tuyere structure be apertured to permit of sufficient air supply for combustion, but at the same time prevent fine siftings of the fuel from falling through the air openings to build up an obstruction to the free and properly diffused air supply. It is further desirable to so form the tuyre units relative to each other as'tobafile the air blast to retard its entry into the fuel and evenly diffuse it about the fire bed to thereby prevent spotty blasts or localized air streams from reaching the fuel. Without such baffled diffusion of the air, and wherein spotty blasts of air may enter the fire bed, clinkers are formed due to such localized excess air. This not only causes inefiicient burning of the fuel, but interferes with the consumption of the fuel in fine ashes for convenient or automatic ash removal. For this reason it is desirable that the air supply to the fire bed remain constant and evenly diffused and distributed throughout the entire area of the tuyre. This may only be accomplished wherein the tuyere is so constructed as to prevent the proper distribution-of the air by the openings being plugged up from siftings, and wherein the openings are so baffled as to further distribute and diffuse the air so that it enters the fuel bed evenly throughout its entire area to prevent excess air or blast at any localized part of the bed such as to form clinkers.

For the purpose of constructing a tuyre having the advantages of proper combustion and eliminating the disadvantages as above set forth, this invention contemplates the provision of a series of upwardly and outwardly extending bars individually cast to provide an air duct and formed with baffles to distribute the air from the air duct throughout its fire bed supporting portion, suitably supporting said bars in assembled relation and then providing intermittent bar baffles such as to diffuse the distributed air evenly throughout the entire fuel supporting surface,

said baffles actin to provide the fuel supporting surface with means to prevent siftings of the fuel from enterin the air ducts or plugging the air diffusing openings.

In the burning of solid fuel on a tuyre structure of the character herein disclosed, the rate of burning is not uniform over the entire area. It is much faster near the center where the fuel is being fed and decreases toward the outer edges. Therefore, this invention contemplates controlling the admission of air to permit of more air where it is required and less air in those areas where the burning rate is slower.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

Fig. 1 is a central vertical section through a retort and tuyre supporting structure showing a portion of a rectangular tuyre in section and a portion in front elevation. Fig. 2 is a section taken on line 2-2 of the upper supporting portion of the tuyre bars with the baffles mounted thereover. Fig. 3 is a section taken on the line 3-3 of the lower portion of the bars with the baffles mounted thereover. Fig, 4 is a perspective view of one of the bafiles. Fig. 5 is a perspective view of one of the bars. Fig. 6 is a plan View of the tuyre, parts of which are illustrated in Figs. 1 to 5, inclusive. Fig. 7 is a partial plan View of the modified form of the invention as applied to a circular tuyre structure. Fig. 8 is a central vertical section through substantially one-half of the circular tuyere structure shown in Fig. 7. Fig. ii is a section taken on the line 99 of Fig. 8. Fig. 10 is a perspective view of one of the baffles of the circular tuyre shown in Figs. 7 and 8. Fig. 11 is a perspective View showing the upper portion of the bar of the circular form of tuyre shown in Figs. '7 and 8.

In the drawings there is illustrated a tuyre construction embodying, as shown in Fig. 1, a retort l0 into which the solid fuel, such as anthracite, is fed upwardly by a screw feed stoker in the usual manner. Extending outwardly from the retort and either cast integrally therewith or rigidly secured thereto there is provided a tuyre supporting structure comprising a ledge ll, an outer supporting ring 12, all surrounded by a wind box wall is formed of refractory material with a supporting ledge 4. The tuyre structur is mounted and supported upon the ledge H, support l2 and ledge M of the wind box wall [3. In the usual manner air is discharged under forced draft into the wind box under the tuyre structure.

The tuyere extends upwardly and outwardly from the retort and within the wall [3 so as to confine the fire bed of the fuel within the lower vertical portion of the tuyre while permitting it to discharge over the upper surface thereof. The structure comprises a series of assembled tuyere bars id, as shown in Fig. 5, and intermediate baffles I6 illustrated in Fig. 4. Said bars and baffles conform in shape, each bar is provided with a base portion ll resting upon the ledge H and the support l2 with a projecting hook l8 extending under the ledge l I. They are each provided with a corresponding rear web portion 19, terminating in an outer portion 2b in supporting engagement with the ledge M. Thus, each of the bars are individually and independently supported in assembly to form with the baffles a com plete enclosed fuel retaining and supporting tuyre.

Each bar has its fuel supporting surface indicated at 2 l formed wtih inwardly tapering walls terminating at the cored opening indicated at 23. Spaced at intervals along the tapered walls 22 there are cast lugs 2d with their side surfaces extending perpendicularly to the fuel supporting face 2!, and extending inwardly partially to the opening 23. The outer face of each of the lugs is slightly spaced outwardly from the corresponding edge of the face of the bar so that such edge is in effect slightly raised therebetween.

In between each adjacent bar there is Sand wiched a bafile it, the web portion idea of this baflie lying against and embraced by opposed lug-s 24 of the bar, wherefore the web portion [9a of the baffle is slightly spaced from the adjacent edges of the fuel supporting surface 2! to permit air to escape therebetween.

The outer portion of the baffles is formed with a baflling flange 25, being substantially T-shape in cross section in association with the web portion lfia. The exposed inner surfaces of the baffling flange '25 is notched or serrated as indicated at 2B, the serrations bearing directly against opposed side portions of the opposed face on the bars, as shown in Figs. 2 and 3. However, the lower portion of the bafilcs, that portion which extends upwardly from the retort, may preferably have one side thereof charnfered, as indicated at 21. At the forward end of the bailie there is a base portion Ha adapted to rest upon the ledge l l and the support l2, said base portion being provided with a projecting hook 18a arranged to extend under the ledge ll. Extending rearwardly from the base portion il'a. there is a web portion lso. terminating in an outer and downwardly extending tongue portion sea, said tongue portion being arranged for supporting engagement with the ledge l5. Ihus, each of the baffles is individually and independently supported in assembly to form with their associated and corresponding bars it a complete, enclosed fuel retaining and supporting tuyere.

By reason of this tuyere construction, as the fuel rises to the combustion area of the fuel bed, within the confines of the bars, air is gently introduced evenly about the combustion area by reason of its forced passage from the wind box surrounding the tuyre between the spaced lugs 24 of the bars through the elongated slot provided by the slight spacing between the bars and the web portion of the baflies. As it passes therebetween it is trapped within the several serrations 26 so as to be pocketed thereby before reaching the fuel. The only escape, therefore, is laterally from between the serrations into the fuel bed, each serration acting as an independent air nozzle laterally directed. By this means the air is distributed and prevented from channelling the fuel so that excess blasts of air are localized.

The air is not only prevented from developing spotty blasts, such as to form clinkers, but is distributed by the multiplicity of serrations which in effect provide laterally directed air nozzles. Additionally, the bafiling flange 25 provides a supporting surface for the fuel as well as a portion of the surface 2% of the bars Hi. The overlapping character of the supporting surfaces, coupled with their protection of the laterally directed air openings, prevents siftings of the fuel particles from having any tendency to fall through or into the air openings or ducts. Consequently there is no plugging up of the air openings, so that distribution of the air supply remains constant throughout the entire fuel supporting surface of the tuyere. As illustrated in Fig. l, the angularly extending supporting portions 2c of the tuyre bars and flanges are held in place on the ledge M by refractory material being lapped thereover in such manner as to prevent their dislocation while the fire is being cleaned.

As it is desirable to introduce more air to the outer portions of the tuyere than to the faster burning central portions thereof, the serrations are so formed on the baffle flanges as to control the air distribution over the surface of the tuyre to admit more air over the outer portions than the inner portions, as in Fig. 4;. It may be noted that for this purpose the serrations areformed of pro gressively less width from the outer to the inner portions of the tuyere.

In the modified form of the invention shown in Figs. 7 to 11, inclusive, the same principle of construction is illustrated as applied to a circular tuyre wherein the retort it! supports a series of concentric rings liila, and from which the retort casing H3 extends upwardly and outwardly to provide an annular support H t, the air from the forced draft being directed into the tuyere. Supported about the periphery of the top ring llila there is a series of bars H5, each extending upwardly and outwardly in a vertical radial plane through the center of the tuyere. Said bars flare outwardly and upwardly to conform with the flared formation of the tuyre structure, theirupper ends being supported on the annular support H4.

Supported intermediate each of said bars, there is a bafile lit similarly supported at its lower end on the top ring HM and at its upper end on the support 5 M. For this purpose the lower end of the ballie is notched at l Na and provided with a lip 5 idea to interlock with the top ring, and at the other end is formed with a downwardly extending lug lilfla to interlock with agroove formed in the support 5 i l. The inner portion of the baffie is flanged at I25 to partially overlap the adjacent exposed surfaces of the bars H5 so that the fuel supporting surface of the tuyere comprises alternately the flange I25 and the intermediate exposed surface of the bar H5.

The bars and baffles may be spaced laterally relative to each other by any suitable means "or by their formation, there being herein illustrated a projection l2d formed on the bars to space them from the lower portion of the baiiies, coupled with a head l2 la of greater width to effect the spacing thereof from the upper end. This is to permit the passage of air between the adjacent portions of the bars and bafiles.

The underside. of the flange I725 isjformed with a plurality of serrations or inwardly extending projections I26 which act to space the overlapping fiange from the fuel supporting surface of the bars so that the air may pass therebetween to the fuel. As above discussed, the serrations I26 cause the air to be diffused and localized so as to discharge as from a plurality of laterally directed nozzles throughout and about the entire area of the fuel bed.

The invention claimed is:

1. A tuyre construction for solid fuel underfeed stokers, including a retort through which the fuel is fed upwardly, a tuyere bar supporting frame extending outwardly therefrom, a plurality of tuyre bars supported to extend upwardly and outwardly upon said frame about the upper portion of said retort, each of said bars being exposed to an air chamber and having a fuel supporting surface with a web portion formed with inwardly inclined surfaces, a baifie T-shaped in cross section having a web portion thereof sup-.-

ported on said frame between each of said bars and having a baffling flange partially overlapping said bars to jointly present therewith a fuel supporting surface, spacing lugs on opposite surfaces of each bar web portion to engage and space the web portion of said baflle laterally therefrom for air admission and distribution therebetween, and a, series of serrations formed inwardly of said flange to diffuse and direct the air laterally over the fuel supporting surfaces of said bars, the effective openings provided by said serrations decreasing from the outer to the inner portions of the tuyre to admit more air to that portion of the tuyere on which the fuel may normally burn more slowly than that portion on which the fuel may normally burn faster.

2. A tuyre construction for supporting a fire bed of solid fuel adapted to admit and diffuse air while preventing siftings of the fuel therethrough, comprising a support conforming thereto, a series of tuyere bars individually supported by said support to extend upwardly and outwardly, each of said bars including a web portion having a thickened section adjacent its outer periphery, a series of bafiles supported between each of said bars, said baflies being flanged to conform to and. overlap the adjacent portions of the respective bars to jointly therewith provide a fuel supporting surface, a plurality of spaced projections on each side of said bars for spacing said bars and said baflies laterally relative to each other to provide air spaces therebetween, each of said air spaces being constricted by said thickened section, and a series of spaced projections between said bars and the flanges of said baiiies, the spaces between said projections forming passages to permit passage of the air while diffusing and directing the air laterally to the fuel.

EDWARD B. THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 341,924 Landis May 18, 1886 1,602,706 Riley Oct. 12, 1926 1,836,395 Rich Dec. 15, 1931 1,881,720 Leach Oct. 11, 1932 1,946,850 Goss et a1. Feb. 13, 1934 1,965,704 Lajoie July 10, 1934 1,978,106 Harrison Oct. 23, 1934 2,016,869 McCrone Oct. 8, 1935 2,106,621 Paige Jan. 25, 1938 2,146,557 Bardes et a1 Feb. 7, 1939 2,149,539 Mosshart Mar. 7, 1939 FOREIGN PATENTS Number Country Date 547,656 Germany Mar. 17, 1932 

